The present invention relates to a method of mounting an IC component to a flat panel display such as a liquid crystal display or a plasma display by bonding the electrodes, specifically, bumps on the electrodes of the IC component to the electrodes of the flat panel display.
A prior art method for bonding an IC component to a flat panel display is shown in FIGS. 27A1 through 28.
In FIGS. 27A1 and 27A2, each IC component for driving a flat panel display is prepared by taking an IC chip (CSP: Chip Size Package) out of a wafer 71 and providing the electrodes on the rear surface thereof with plating bumps. On the other hand, in step S50 shown in FIG. 28, a liquid crystal display (LCD) panel as shown in FIG. 27B is placed in a specified position. In step S51, an anisotropic conductive adhesive or film (ACF, or anisotropic conductive sheet) 20 is attached to electrodes 2a provided on the periphery of a liquid crystal display panel 2. In step S52, each IC component 5 sucked by a component suction unit is aligned in position with the flat panel display 2, and the IC component 5 is temporarily bonded (pre-mounted under pressure) onto the anisotropic conductive adhesive or film 20 of the flat panel display 2 by means of a pressurizing tool 70. Then, in step S54, each flexible board is connected to the flat panel display 2. In step S55, the flat panel display 2 is subjected to an image electric inspection process. In this stage, it is decided whether or not the IC component 5 mounted on the flat panel display 2 can operate. If the IC component 5 is defective, the program flow proceeds to step S59 to remove the IC component 5 from the flat panel display 2 and mount another new IC component 5. When the IC component 5 is a good one, in step S56, the IC component 5 is regularly or properly bonded (mounted under pressure) to the anisotropic conductive adhesive or film 20 of the flat panel display 2 at a temperature and a pressurizing force that are higher than those in the temporary bonding process. Subsequently, in step S57, the IC component 5 and the anisotropic conductive adhesive or film 20 are coated with protection resin. In step S58, the flat panel display 2 mounted with each IC component 5 is stored in a specified position.
However, according to the above-mentioned bonding method, a lot of actual IC components have been used to be mounted onto the flat panel display for the purpose of finding an offset amount for cancelling a positional alignment error when aligning in position the IC component 5 with the flat panel display 2, and this has also resulted in the wastefulness of the IC components and requirement of much labor.
Furthermore, each IC component is mounted to the flat panel display via the anisotropic conductive adhesive or film. Therefore, even when the IC component and the flat panel display are accurately aligned in position with each other before mounting the IC component, the IC component slips with respect to the flat panel display due to the viscosity of the anisotropic conductive adhesive or film in the mounting stage, possibly causing a significant displacement of the IC component relative to the flat panel display after the IC component is mounted.
On the other hand, due to the warping of the flat panel display, a parallelism of the IC component relative to the flat panel display is possibly disordered. Furthermore, depending on the parallelism of a pressurizing tool for pressurizing the IC component against the flat panel display, the parallelism of the IC component relative to the flat panel display is possibly disordered. Therefore, the parallelism of the IC component relative to the flat panel display is required to be controlled within a specified tolerance range.
Measurement of the parallelism has been performed by measuring collapse of conductive particles in the anisotropic conductive adhesive or film or hue of bumps attached to the electrodes of the IC component by means of a microscope to measure the parallelism at a plurality of portions of the bonding portion of the IC component and the flat panel display. However, different measurement results may be produced depending on different microscopes, and if the positional relationship between the microscope and the bonding portion of the IC component and the flat panel display varies at each of the portions, different optical reflectance values result. This also causes an error in the measurement of the parallelism, meaning that the measurement of the parallelism has been difficult. Furthermore, when operators evaluate the parallelism, the operators become sensuous and produce different evaluation results due to differences between individuals, meaning that the evaluation lacks objectivity and can not be quantified.